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<div class="doctools">
<h1 class="doctools_title">critcl::bitmap(n) 1.0.1 doc &quot;C Runtime In Tcl (CriTcl)&quot;</h1>
<div id="name" class="doctools_section"><h2><a name="name">Name</a></h2>
<p>critcl::bitmap - CriTcl Utilities: Bitset en- and decoding</p>
</div>
<div id="toc" class="doctools_section"><h2><a name="toc">Table Of Contents</a></h2>
<ul class="doctools_toc">
<li class="doctools_section"><a href="#toc">Table Of Contents</a></li>
<li class="doctools_section"><a href="#synopsis">Synopsis</a></li>
<li class="doctools_section"><a href="#section1">Description</a></li>
<li class="doctools_section"><a href="#section2">API</a></li>
<li class="doctools_section"><a href="#section3">Example</a></li>
<li class="doctools_section"><a href="#section4">Authors</a></li>
<li class="doctools_section"><a href="#section5">Bugs, Ideas, Feedback</a></li>
<li class="doctools_section"><a href="#keywords">Keywords</a></li>
<li class="doctools_section"><a href="#category">Category</a></li>
<li class="doctools_section"><a href="#copyright">Copyright</a></li>
</ul>
</div>
<div id="synopsis" class="doctools_section"><h2><a name="synopsis">Synopsis</a></h2>
<div class="doctools_synopsis">
<ul class="doctools_requirements">
<li>package require <b class="pkgname">Tcl 8.4</b></li>
<li>package require <b class="pkgname">critcl <span class="opt">?3.1.11?</span></b></li>
<li>package require <b class="pkgname">critcl::bitmap <span class="opt">?1.0.1?</span></b></li>
</ul>
<ul class="doctools_syntax">
<li><a href="#1"><b class="cmd">::critcl::bitmap::def</b> <i class="arg">name</i> <i class="arg">definition</i> <span class="opt">?<i class="arg">exclusions</i>?</span></a></li>
</ul>
</div>
</div>
<div id="section1" class="doctools_section"><h2><a name="section1">Description</a></h2>
<p><i class="term">C Runtime In Tcl</i>, or <i class="term"><a href="critcl_pkg.html">CriTcl</a></i> , is a system for compiling C code
embedded in Tcl on the fly and either loading the resulting objects into Tcl for
immediate use or packaging them for distribution.  Use <i class="term"><a href="critcl_pkg.html">CriTcl</a></i> to improve
performance by rewriting in C those routines that are performance bottlenecks.</p>
<p>This document is the reference manpage for the
<b class="package">critcl::bitmap</b> package. This package provides convenience
commands for advanced functionality built on top of both critcl core
and package <b class="package"><a href="critcl_iassoc.html">critcl::iassoc</a></b>.</p>
<p>C level libraries often use bit-sets to encode many flags into a
single value. Tcl bindings to such libraries now have the task of
converting a Tcl representation of such flags (like a list of strings)
into such bit-sets, and back.
<em>Note</em> here that the C-level information has to be something which
already exists. The package does <em>not</em> create these values. This is
in contrast to the package <b class="package"><a href="critcl_enum.html">critcl::enum</a></b> which creates an
enumeration based on the specified symbolic names.</p>
<p>This package was written to make the declaration and management
of such bit-sets and their associated conversions functions easy,
hiding all attendant complexity from the user.</p>
<p>Its intended audience are mainly developers wishing to write
Tcl packages with embedded C code.</p>
<p>This package resides in the Core Package Layer of CriTcl.</p>
<p><img alt="arch_core" src="../image/arch_core.png"></p>
</div>
<div id="section2" class="doctools_section"><h2><a name="section2">API</a></h2>
<dl class="doctools_definitions">
<dt><a name="1"><b class="cmd">::critcl::bitmap::def</b> <i class="arg">name</i> <i class="arg">definition</i> <span class="opt">?<i class="arg">exclusions</i>?</span></a></dt>
<dd><p>This command defines two C functions for the conversion of the
<i class="arg">name</i>d bit-set into Tcl lists, and vice versa.
The underlying mapping tables are automatically initialized on first
access, and finalized on interpreter destruction.</p>
<p>The <i class="arg">definition</i> dictionary provides the mapping from the
Tcl-level symbolic names of the flags to their C expressions (often
the name of the macro specifying the actual value).
<em>Note</em> here that the C-level information has to be something which
already exists. The package does <em>not</em> create these values. This is
in contrast to the package <b class="package"><a href="critcl_enum.html">critcl::enum</a></b> which creates an
enumeration based on the specified symbolic names.</p>
<p>The optional <i class="arg">exlusion</i> list is for the flags/bit-sets for
which conversion from bit-set to flag, i.e. decoding makes no
sense. One case for such, for example, are flags representing a
combination of other flags.</p>
<p>The package generates multiple things (declarations and
definitions) with names derived from <i class="arg">name</i>, which has to be a
proper C identifier.</p>
<dl class="doctools_definitions">
<dt><i class="arg">name</i>_encode</dt>
<dd><p>The function for encoding a Tcl list of strings into the equivalent
bit-set.
Its signature is</p>
<pre class="doctools_example">
int <i class="arg">name</i>_encode (Tcl_Interp* interp, Tcl_Obj* flags, int* result);
</pre>
<p>The return value of the function is a Tcl error code,
i.e. <b class="const">TCL_OK</b>, <b class="const">TCL_ERROR</b>, etc.</p></dd>
<dt><i class="arg">name</i>_decode</dt>
<dd><p>The function for decoding a bit-set into the equivalent Tcl list of
strings.
Its signature is</p>
<pre class="doctools_example">
Tcl_Obj* <i class="arg">name</i>_decode (Tcl_Interp* interp, int flags);
</pre>
</dd>
<dt><i class="arg">name</i>.h</dt>
<dd><p>A header file containing the declarations for the two conversion
functions, for use by other parts of the system, if necessary.</p>
<p>The generated file is stored in a place where it will not
interfere with the overall system outside of the package, yet also be
available for easy inclusion by package files (<b class="cmd">csources</b>).</p></dd>
<dt><i class="arg">name</i></dt>
<dd><p>The name of a critcl argument type encapsulating the encoder function
for use by <b class="cmd">critcl::cproc</b>.</p></dd>
<dt><i class="arg">name</i></dt>
<dd><p>The name of a critcl result type encapsulating the decoder function
for use by <b class="cmd">critcl::cproc</b>.</p></dd>
</dl></dd>
</dl>
</div>
<div id="section3" class="doctools_section"><h2><a name="section3">Example</a></h2>
<p>The example shown below is the specification of the event flags pulled
from the draft work on a Tcl binding to Linux's inotify APIs.</p>
<pre class="doctools_example">
package require Tcl 8.5
package require critcl 3.1.11
critcl::buildrequirement {
    package require critcl::bitmap
}
critcl::bitmap::def tcl_inotify_events {
    accessed       IN_ACCESS
    all            IN_ALL_EVENTS
    attribute      IN_ATTRIB
    closed         IN_CLOSE
    closed-nowrite IN_CLOSE_NOWRITE
    closed-write   IN_CLOSE_WRITE
    created        IN_CREATE
    deleted        IN_DELETE
    deleted-self   IN_DELETE_SELF
    dir-only       IN_ONLYDIR
    dont-follow    IN_DONT_FOLLOW
    modified       IN_MODIFY
    move           IN_MOVE
    moved-from     IN_MOVED_FROM
    moved-self     IN_MOVE_SELF
    moved-to       IN_MOVED_TO
    oneshot        IN_ONESHOT
    open           IN_OPEN
    overflow       IN_Q_OVERFLOW
    unmount        IN_UNMOUNT
} {
    all closed move oneshot
}
# Declarations:          tcl_inotify_events.h
# Encoder:      int      tcl_inotify_events_encode (Tcl_Interp* interp, Tcl_Obj* flags, int* result);
# Decoder:      Tcl_Obj* tcl_inotify_events_decode (Tcl_Interp* interp, int flags);
# crit arg-type          tcl_inotify_events
# crit res-type          tcl_inotify_events
</pre>
</div>
<div id="section4" class="doctools_section"><h2><a name="section4">Authors</a></h2>
<p>Andreas Kupries</p>
</div>
<div id="section5" class="doctools_section"><h2><a name="section5">Bugs, Ideas, Feedback</a></h2>
<p>This document, and the package it describes, will undoubtedly contain
bugs and other problems.
Please report such at <a href="https://github.com/andreas-kupries/critcl">https://github.com/andreas-kupries/critcl</a>.
Please also report any ideas for enhancements you may have for either
package and/or documentation.</p>
</div>
<div id="keywords" class="doctools_section"><h2><a name="keywords">Keywords</a></h2>
<p><a href="../index.html#key8">C code</a>, <a href="../index.html#key3">Embedded C Code</a>, <a href="../index.html#key15">Tcl Interp Association</a>, <a href="../index.html#key12">bitmask</a>, <a href="../index.html#key11">bitset</a>, <a href="../index.html#key6">code generator</a>, <a href="../index.html#key0">compile &amp; run</a>, <a href="../index.html#key10">compiler</a>, <a href="../index.html#key1">dynamic code generation</a>, <a href="../index.html#key2">dynamic compilation</a>, <a href="../index.html#key14">flags</a>, <a href="../index.html#key9">generate package</a>, <a href="../index.html#key4">linker</a>, <a href="../index.html#key5">on demand compilation</a>, <a href="../index.html#key7">on-the-fly compilation</a>, <a href="../index.html#key13">singleton</a></p>
</div>
<div id="category" class="doctools_section"><h2><a name="category">Category</a></h2>
<p>Glueing/Embedded C code</p>
</div>
<div id="copyright" class="doctools_section"><h2><a name="copyright">Copyright</a></h2>
<p>Copyright &copy; 2011-2018 Andreas Kupries</p>
</div>
</div></body></html>
